1. Field of the Invention
The present invention generally relates to packaging and finishing paper envelopes during the envelope manufacturing process and is more specifically directed to a package of vertically aligned plural envelopes secured in a unitized stack using plural adhesive spots to secure each envelope in the stack to a superior or subjacent envelope. The present invention is also directed to a method for producing such a unitized stack and to apparatus for carrying out the method.
2. Prior Art
It has been conventional practice to provide banded stacks of paper envelopes vertically aligned one on top of the other with the envelopes being held in position by a band of paper, cellophane or the like encircling the envelope stack midway between the ends of the envelopes in a beltlike manner. A shortcoming of such banded envelope stacks is that after a few envelopes are removed, the remaining envelopes are loosely held in the stack and easily become disassociated from the stack. Another disadvantage of such banded envelope stacks is that the banding apparatus for forming such stacks is expensive and the cost of installing such apparatus on a conventional envelope machine is approximately $65,000 while the cost of installing the subject invention is only approximately $12,000. A further advantage of the present invention is that it is usable with envelopes of practically any size, whereas conventional banding apparatus is only usable for banding envelopes in a restricted size range. A further advantage of the present inventive apparatus is that it can be easily removed from one envelope machine and installed on another envelope machine.
Prior art investigators have attempted to produce a unitized arrangement of bags by adhering adjacent bags using adhesive. For example, Wing U.S. Pat. Nos. 3,587,844 and 3,587,845, both disclose an elongated strip array of heat shrinkable plastic bags held together in an imbricated manner by adhesive or two-sided tape. The '844 patent discloses an elongated chain of overlapping imbricated bags which are held together with splotches of adhesive such as 20 and 21 shown on bag 22. The '845 patent is the same as the '844 patent except that the adhesive splotches are replaced with two small swatches of two-faced adhesive members 20 and 21 or by heat and pressure as illustrated in FIG. 5 of the patent.
Farrelly et al., U.S. Pat. No. 3,915,302, discloses an elongated strip of overlapping plastic bags attached to a pair of adhesive tapes 50 and 52. Adhesive means 34 releasable adheres the lower side of bag 10 to the upper side of bag 30, while adhesive means 44 in like manner releasable adheres the lower side of bag 30 to the upper side of bag 44.
Perecman, U.S. Pat. No. 4,502,599, discloses a pack of resealable plastic bags which is formed by stacking the bags directly on top of one another in vertical alignment (i.e., not overlapped or imbricated), with the package being held together by adhering one bag to the next with a strip of pressure sensitive adhesive on the sealing flap of each successive bag connected to the back of the sealing flap of the bag on top of it.
Wilson, U.S. Pat. No. 4,674,634, also discloses a stack of plastic bags which are held together by a reclosable adhesive seal on each bag flap. However, the bags are stacked with the flaps at alternate opposite edges of the stack as shown in FIG. 4 of the patent.
Membrino, U.S. Pat. No. 4,500,000, discloses a pad of open mouthed plastic bags overlying each other and separably connected by a common base portion.
Other investigators have developed apparatus for securing plural bags using adhesive. For example, Farrelly, et al., U.S. Pat. No. 4,534,752, discloses an apparatus for securing the top ends of sack gussets. In FIG. 7, two adhesive guns, 48 and 49, are mounted over two slots 75 in a bracket 65 to apply glue to sacks passing beneath the bracket.
Stemmler, U.S. Pat. No. 3,400,642, discloses an envelope folding and gumming apparatus with a cylinder 22 having applicator segments 23 attached on opposite sides. Adhesive from reservoir 26 is applied to the applicators 23 by a roller 25. The applicators 23 then come in contact with the side flaps of envelopes upon rotation of cylinder 22.
Cone, U.S. Pat. No. 4,373,986, discloses a gluing machine with glue applicator assembly 22 (located in upper right side of FIGS. 1 and 3) which deposits glue at spaced-apart intervals on a continuous carrier sheet C. Projections 284 on a raised transfer roller 280 determine the pattern and spacing of the glue applied to carrier sheet C by pushing the sheet into contact with adhesive coated roller 290. The carrier sheet C is then contacted with the material to be glued.
Dohnalic, U.S. Pat. No. 3,450,009, discloses an envelope making machine with rotary applicators 82A and 82B (see FIGS. 4 and S) mounted on a shaft 94. The rotary applicators 82A and 82B apply adhesive in a V-shaped pattern to the edged portions of envelopes as they are directed past them by roller 80.
Helm, U.S. Pat. No. 3,630,125 shows the continuous application of a band of adhesive to overlapped edges of envelopes. The size of the glue patch is controlled by the amount of overlap of the envelopes.
Helm U.S. Pat. No. 3,747,561, discloses an adhesive application mechanism for envelope processing machinery, in which an adhesive applicator roll 10 is located inside an adhesive box 22. The adhesive box 22 ma be operated remotely, or manually when necessary, in order to raise the adhesive box 22 to prevent the transfer of adhesive to the applicator dies (not shown) which apply the adhesive to the flaps of envelopes.
Helm U.S. Pat. No. 4,138,933, discloses an apparatus for gumming and folding open-end envelopes which uses a cylinder 66 (see FIG. 2) to apply adhesive to envelope flaps. The adhesive is provided by roller 74 from adhesive reservoir 72. The envelope folding apparatus of the '933 patent is similar in construction to the Smithe RA-800-type folding machine used in the present invention. Smithe et al., U.S. Pat. No. 3,641,883, discloses a method and apparatus for folding a closure flap of an envelope. Helm, U.S. Pat. No. 3,745,894 also utilizes a flap folding apparatus. Bethke, U.S. Pat. No. 3,847,384, discloses a collating machine with many elements in common with the other Smithe envelope folding and gluing machines.
Thus, the prior art fails to show a unitized bonded stack of paper envelopes held together by the careful placement of two adhesive splotches on the front of each envelope which enable each envelope to adhere to the back of the envelope placed directly on top of it. The prior disclosures relating to envelope folding and gumming machines generally relate to placing a strip of glue near or at the edge of the flaps on envelopes. The gumming machines, such as those disclosed by Stemmler, Hornung and Helm, generally use a roller to apply the adhesive. Cone utilized a continuous carrier sheet from which glue was then applied to envelopes or sheets of material.
Farrell et al., U.S. Pat. No. 4,534,752 discloses the use of two adhesive guns mounted over slots in a bracket to apply glue to gussets of large sacks such as those used for selling pet food and the like.
The present invention uses two Vansco high-speed actuators with applicator heads in alignment with two slots cut through the steel flap trap plate of a Smithe RA-800-type fold machine in a similar fashion to the '752 patent. Certain disadvantages of the prior art are overcome through the use of a dual-counter mechanism installed on a conventional envelope machine to count the number of envelopes which have been processed in a batch, the use of a releasable type of adhesive, placement of the adhesive in a specific location on envelopes, and providing novel timing and processing by which the items to be glued are brought before the adhesive applicators, each of which "spits" a dot of glue onto each envelope following which the envelopes are forwarded to further processing steps. The delivery cylinder of the folding machine is provided with two grooves which match the slots in the steel flap trap plate to thereby prevent adhesive on the envelopes from being wiped onto the cylinder when the cylinder removes the envelope from the flap trap plate for transfer to the delivery spiral. The present invention associates envelopes directly against one another soon after the adhesive is applied so as to provide a stack when the adhesive dots dry.
Therefore, the prior art appears deficient in showing a unitary device and/or method which performs all of the functions of the present invention.